arch/powerpc/mm/pgtable_32.c

   1 /*
   2  * This file contains the routines setting up the linux page tables.
   3  *  -- paulus
   4  *
   5  *  Derived from arch/ppc/mm/init.c:
   6  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   7  *
   8  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
   9  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  10  *    Copyright (C) 1996 Paul Mackerras
  11  *
  12  *  Derived from "arch/i386/mm/init.c"
  13  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  14  *
  15  *  This program is free software; you can redistribute it and/or
  16  *  modify it under the terms of the GNU General Public License
  17  *  as published by the Free Software Foundation; either version
  18  *  2 of the License, or (at your option) any later version.
  19  *
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include <linux/mm.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/init.h>
  28 #include <linux/highmem.h>
  29 #include <linux/memblock.h>
  30 #include <linux/slab.h>
  31
  32 #include <asm/pgtable.h>
  33 #include <asm/pgalloc.h>
  34 #include <asm/fixmap.h>
  35 #include <asm/io.h>
  36
  37 #include "mmu_decl.h"
  38
  39 unsigned long ioremap_base;
  40 unsigned long ioremap_bot;
  41 EXPORT_SYMBOL(ioremap_bot);     /* aka VMALLOC_END */
  42
  43 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
  44 #define HAVE_BATS       1
  45 #endif
  46
  47 #if defined(CONFIG_FSL_BOOKE)
  48 #define HAVE_TLBCAM     1
  49 #endif
  50
  51 extern char etext[], _stext[];
  52
  53 #ifdef HAVE_BATS
  54 extern phys_addr_t v_mapped_by_bats(unsigned long va);
  55 extern unsigned long p_mapped_by_bats(phys_addr_t pa);
  56 void setbat(int index, unsigned long virt, phys_addr_t phys,
  57             unsigned int size, int flags);
  58
  59 #else /* !HAVE_BATS */
  60 #define v_mapped_by_bats(x)     (0UL)
  61 #define p_mapped_by_bats(x)     (0UL)
  62 #endif /* HAVE_BATS */
  63
  64 #ifdef HAVE_TLBCAM
  65 extern unsigned int tlbcam_index;
  66 extern phys_addr_t v_mapped_by_tlbcam(unsigned long va);
  67 extern unsigned long p_mapped_by_tlbcam(phys_addr_t pa);
  68 #else /* !HAVE_TLBCAM */
  69 #define v_mapped_by_tlbcam(x)   (0UL)
  70 #define p_mapped_by_tlbcam(x)   (0UL)
  71 #endif /* HAVE_TLBCAM */
  72
  73 #define PGDIR_ORDER     (32 + PGD_T_LOG2 - PGDIR_SHIFT)
  74
  75 pgd_t *pgd_alloc(struct mm_struct *mm)
  76 {
  77         pgd_t *ret;
  78
  79         /* pgdir take page or two with 4K pages and a page fraction otherwise */
  80 #ifndef CONFIG_PPC_4K_PAGES
  81         ret = kzalloc(1 << PGDIR_ORDER, GFP_KERNEL);
  82 #else
  83         ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  84                         PGDIR_ORDER - PAGE_SHIFT);
  85 #endif
  86         return ret;
  87 }
  88
  89 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  90 {
  91 #ifndef CONFIG_PPC_4K_PAGES
  92         kfree((void *)pgd);
  93 #else
  94         free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
  95 #endif
  96 }
  97
  98 __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
  99 {
 100         pte_t *pte;
 101         extern int mem_init_done;
 102         extern void *early_get_page(void);
 103
 104         if (mem_init_done) {
 105                 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 106         } else {
 107                 pte = (pte_t *)early_get_page();
 108                 if (pte)
 109                         clear_page(pte);
 110         }
 111         return pte;
 112 }
 113
 114 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 115 {
 116         struct page *ptepage;
 117
 118         gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
 119
 120         ptepage = alloc_pages(flags, 0);
 121         if (!ptepage)
 122                 return NULL;
 123         pgtable_page_ctor(ptepage);
 124         return ptepage;
 125 }
 126
 127 void __iomem *
 128 ioremap(phys_addr_t addr, unsigned long size)
 129 {
 130         return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
 131                                 __builtin_return_address(0));
 132 }
 133 EXPORT_SYMBOL(ioremap);
 134
 135 void __iomem *
 136 ioremap_wc(phys_addr_t addr, unsigned long size)
 137 {
 138         return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
 139                                 __builtin_return_address(0));
 140 }
 141 EXPORT_SYMBOL(ioremap_wc);
 142
 143 void __iomem *
 144 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
 145 {
 146         /* writeable implies dirty for kernel addresses */
 147         if (flags & _PAGE_RW)
 148                 flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
 149
 150         /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
 151         flags &= ~(_PAGE_USER | _PAGE_EXEC);
 152
 153 #ifdef _PAGE_BAP_SR
 154         /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
 155          * which means that we just cleared supervisor access... oops ;-) This
 156          * restores it
 157          */
 158         flags |= _PAGE_BAP_SR;
 159 #endif
 160
 161         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 162 }
 163 EXPORT_SYMBOL(ioremap_prot);
 164
 165 void __iomem *
 166 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
 167 {
 168         return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
 169 }
 170
 171 void __iomem *
 172 __ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
 173                  void *caller)
 174 {
 175         unsigned long v, i;
 176         phys_addr_t p;
 177         int err;
 178
 179         /* Make sure we have the base flags */
 180         if ((flags & _PAGE_PRESENT) == 0)
 181                 flags |= PAGE_KERNEL;
 182
 183         /* Non-cacheable page cannot be coherent */
 184         if (flags & _PAGE_NO_CACHE)
 185                 flags &= ~_PAGE_COHERENT;
 186
 187         /*
 188          * Choose an address to map it to.
 189          * Once the vmalloc system is running, we use it.
 190          * Before then, we use space going down from ioremap_base
 191          * (ioremap_bot records where we're up to).
 192          */
 193         p = addr & PAGE_MASK;
 194         size = PAGE_ALIGN(addr + size) - p;
 195
 196         /*
 197          * If the address lies within the first 16 MB, assume it's in ISA
 198          * memory space
 199          */
 200         if (p < 16*1024*1024)
 201                 p += _ISA_MEM_BASE;
 202
 203 #ifndef CONFIG_CRASH_DUMP
 204         /*
 205          * Don't allow anybody to remap normal RAM that we're using.
 206          * mem_init() sets high_memory so only do the check after that.
 207          */
 208         if (mem_init_done && (p < virt_to_phys(high_memory)) &&
 209             !(__allow_ioremap_reserved && memblock_is_region_reserved(p, size))) {
 210                 printk("__ioremap(): phys addr 0x%llx is RAM lr %p\n",
 211                        (unsigned long long)p, __builtin_return_address(0));
 212                 return NULL;
 213         }
 214 #endif
 215
 216         if (size == 0)
 217                 return NULL;
 218
 219         /*
 220          * Is it already mapped?  Perhaps overlapped by a previous
 221          * BAT mapping.  If the whole area is mapped then we're done,
 222          * otherwise remap it since we want to keep the virt addrs for
 223          * each request contiguous.
 224          *
 225          * We make the assumption here that if the bottom and top
 226          * of the range we want are mapped then it's mapped to the
 227          * same virt address (and this is contiguous).
 228          *  -- Cort
 229          */
 230         if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
 231                 goto out;
 232
 233         if ((v = p_mapped_by_tlbcam(p)))
 234                 goto out;
 235
 236         if (mem_init_done) {
 237                 struct vm_struct *area;
 238                 area = get_vm_area_caller(size, VM_IOREMAP, caller);
 239                 if (area == 0)
 240                         return NULL;
 241                 area->phys_addr = p;
 242                 v = (unsigned long) area->addr;
 243         } else {
 244                 v = (ioremap_bot -= size);
 245         }
 246
 247         /*
 248          * Should check if it is a candidate for a BAT mapping
 249          */
 250
 251         err = 0;
 252         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 253                 err = map_page(v+i, p+i, flags);
 254         if (err) {
 255                 if (mem_init_done)
 256                         vunmap((void *)v);
 257                 return NULL;
 258         }
 259
 260 out:
 261         return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
 262 }
 263 EXPORT_SYMBOL(__ioremap);
 264
 265 void iounmap(volatile void __iomem *addr)
 266 {
 267         /*
 268          * If mapped by BATs then there is nothing to do.
 269          * Calling vfree() generates a benign warning.
 270          */
 271         if (v_mapped_by_bats((unsigned long)addr)) return;
 272
 273         if (addr > high_memory && (unsigned long) addr < ioremap_bot)
 274                 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
 275 }
 276 EXPORT_SYMBOL(iounmap);
 277
 278 int map_page(unsigned long va, phys_addr_t pa, int flags)
 279 {
 280         pmd_t *pd;
 281         pte_t *pg;
 282         int err = -ENOMEM;
 283
 284         /* Use upper 10 bits of VA to index the first level map */
 285         pd = pmd_offset(pud_offset(pgd_offset_k(va), va), va);
 286         /* Use middle 10 bits of VA to index the second-level map */
 287         pg = pte_alloc_kernel(pd, va);
 288         if (pg != 0) {
 289                 err = 0;
 290                 /* The PTE should never be already set nor present in the
 291                  * hash table
 292                  */
 293                 BUG_ON((pte_val(*pg) & (_PAGE_PRESENT | _PAGE_HASHPTE)) &&
 294                        flags);
 295                 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
 296                                                      __pgprot(flags)));
 297         }
 298         return err;
 299 }
 300
 301 /*
 302  * Map in a chunk of physical memory starting at start.
 303  */
 304 void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 305 {
 306         unsigned long v, s, f;
 307         phys_addr_t p;
 308         int ktext;
 309
 310         s = offset;
 311         v = PAGE_OFFSET + s;
 312         p = memstart_addr + s;
 313         for (; s < top; s += PAGE_SIZE) {
 314                 ktext = ((char *) v >= _stext && (char *) v < etext);
 315                 f = ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL;
 316                 map_page(v, p, f);
 317 #ifdef CONFIG_PPC_STD_MMU_32
 318                 if (ktext)
 319                         hash_preload(&init_mm, v, 0, 0x300);
 320 #endif
 321                 v += PAGE_SIZE;
 322                 p += PAGE_SIZE;
 323         }
 324 }
 325
 326 void __init mapin_ram(void)
 327 {
 328         unsigned long s, top;
 329
 330 #ifndef CONFIG_WII
 331         top = total_lowmem;
 332         s = mmu_mapin_ram(top);
 333         __mapin_ram_chunk(s, top);
 334 #else
 335         if (!wii_hole_size) {
 336                 s = mmu_mapin_ram(total_lowmem);
 337                 __mapin_ram_chunk(s, total_lowmem);
 338         } else {
 339                 top = wii_hole_start;
 340                 s = mmu_mapin_ram(top);
 341                 __mapin_ram_chunk(s, top);
 342
 343                 top = memblock_end_of_DRAM();
 344                 s = wii_mmu_mapin_mem2(top);
 345                 __mapin_ram_chunk(s, top);
 346         }
 347 #endif
 348 }
 349
 350 /* Scan the real Linux page tables and return a PTE pointer for
 351  * a virtual address in a context.
 352  * Returns true (1) if PTE was found, zero otherwise.  The pointer to
 353  * the PTE pointer is unmodified if PTE is not found.
 354  */
 355 int
 356 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
 357 {
 358         pgd_t   *pgd;
 359         pud_t   *pud;
 360         pmd_t   *pmd;
 361         pte_t   *pte;
 362         int     retval = 0;
 363
 364         pgd = pgd_offset(mm, addr & PAGE_MASK);
 365         if (pgd) {
 366                 pud = pud_offset(pgd, addr & PAGE_MASK);
 367                 if (pud && pud_present(*pud)) {
 368                         pmd = pmd_offset(pud, addr & PAGE_MASK);
 369                         if (pmd_present(*pmd)) {
 370                                 pte = pte_offset_map(pmd, addr & PAGE_MASK);
 371                                 if (pte) {
 372                                         retval = 1;
 373                                         *ptep = pte;
 374                                         if (pmdp)
 375                                                 *pmdp = pmd;
 376                                         /* XXX caller needs to do pte_unmap, yuck */
 377                                 }
 378                         }
 379                 }
 380         }
 381         return(retval);
 382 }
 383
 384 #ifdef CONFIG_DEBUG_PAGEALLOC
 385
 386 static int __change_page_attr(struct page *page, pgprot_t prot)
 387 {
 388         pte_t *kpte;
 389         pmd_t *kpmd;
 390         unsigned long address;
 391
 392         BUG_ON(PageHighMem(page));
 393         address = (unsigned long)page_address(page);
 394
 395         if (v_mapped_by_bats(address) || v_mapped_by_tlbcam(address))
 396                 return 0;
 397         if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
 398                 return -EINVAL;
 399         __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
 400         wmb();
 401         flush_tlb_page(NULL, address);
 402         pte_unmap(kpte);
 403
 404         return 0;
 405 }
 406
 407 /*
 408  * Change the page attributes of an page in the linear mapping.
 409  *
 410  * THIS CONFLICTS WITH BAT MAPPINGS, DEBUG USE ONLY
 411  */
 412 static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
 413 {
 414         int i, err = 0;
 415         unsigned long flags;
 416
 417         local_irq_save(flags);
 418         for (i = 0; i < numpages; i++, page++) {
 419                 err = __change_page_attr(page, prot);
 420                 if (err)
 421                         break;
 422         }
 423         local_irq_restore(flags);
 424         return err;
 425 }
 426
 427
 428 void kernel_map_pages(struct page *page, int numpages, int enable)
 429 {
 430         if (PageHighMem(page))
 431                 return;
 432
 433         change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
 434 }
 435 #endif /* CONFIG_DEBUG_PAGEALLOC */
 436
 437 static int fixmaps;
 438
 439 void __set_fixmap (enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags)
 440 {
 441         unsigned long address = __fix_to_virt(idx);
 442
 443         if (idx >= __end_of_fixed_addresses) {
 444                 BUG();
 445                 return;
 446         }
 447
 448         map_page(address, phys, pgprot_val(flags));
 449         fixmaps++;
 450 }
 451
 452 void __this_fixmap_does_not_exist(void)
 453 {
 454         WARN_ON(1);
 455 }